1. Field of the Invention
The present invention relates to a thin-film transistor, an array substrate having the thin-film transistor and a method of manufacturing the array substrate. More particularly, the present invention relates to a thin-film transistor capable of enhancing the display quality of a display apparatus, an array substrate having the thin-film transistor and a method of manufacturing the array substrate.
2. Description of the Related Art
A liquid crystal display (“LCD”) panel includes an array substrate having a switching element for driving a pixel, an opposite substrate facing the array substrate, and a liquid crystal layer disposed between the array substrate and the opposite substrate. The LCD panel displays an image by applying voltage to the liquid crystal layer to control transmittance of light.
The array substrate includes a thin-film transistor employed as the switching element of the array substrate. The thin-film transistor includes a gate electrode, a source electrode, a drain electrode, and a channel layer. According to the channel layer, the thin-film transistor is classified as either an amorphous silicon thin-film transistor, a poly silicon thin-film transistor, or a cadmium-selenium (“Cd—Se”) thin-film transistor. Conventionally, the thin-film transistor employs amorphous silicon as the channel layer.
An optical band gap of the amorphous silicon is no higher than about 1.8 eV. Therefore, when the amorphous silicon is employed by the thin-film transistor as the channel layer, the amorphous silicon absorbs visible light having a wavelength of about 380 nm to about 780 nm corresponding to energy of 1.59 eV to about 3.26 eV to generate leakage current. When the thin-film transistor employing amorphous silicon is driven, the number of dangling bonds increases to induce an after-image and the thin-film transistor becomes unstable.
In order to solve the problem of the leakage current, the thin-film transistor has been formed as a bottom gate staggered type. However, the active layer activated by light still generates the leakage current since the light is not blocked by a gate electrode.